Olympus Mons is an extinct volcano on Mars. It’s the tallest mountain in the Solar System. This picture of the mountain was taken recently by the Indian Space Research Organization’s Mars Orbiter from an altitude of 8,387 km. The arrow indicates the summit which rises about 21 km above the mean surface level, so high that it’s effectively above the atmosphere. The white area around the mountain is a cloud formation.
Image Credit: ISRO